KR20070076116A - Electro luminescence device - Google Patents

Abstract

An electro luminescence device is provided to increase the surface roughness of a cathode by doping one of Si and Ni on the cathode. An electro luminescence device includes a glass substrate(101), an organic electro luminescent layer(112), a pixel electrode(308), a common electrode(115), a thin film transistor(A), an electron injection layer(110), an electron transport layer(111), a hole transport layer(113), and a hole injection layer(114). A pixel is defined on an area where the pixel electrode(308) and the common electrode(115) intersect on the glass substrate(101). The thin film transistor(A) is formed on the glass substrate(101), and is electrically connected to the pixel electrode(308). The electron injection layer(110) and the electron transport layer(111) are formed between the pixel electrode(308) and the organic electro luminescent layer(112). The hole transport layer(113) and the hole injection layer(114) are formed between the organic electro luminescent layer(112) and the common electrode(115). The pixel electrode(308) is electrically connected to a drain of the thin film transistor(A), and one or both of Si and Ni are doped on the pixel electrode(308).

Description

Electroluminescent device

1 is a cross-sectional view showing a conventional organic electroluminescent device.

FIG. 2 is a diagram for illustrating a thin film state of an Al electrode, which is a cathode of the organic electroluminescent device of FIG. 1, as an example; FIG.

3 is a cross-sectional view showing an EL device as a first embodiment according to the present invention;

4A to 4D are manufacturing process diagrams of the electroluminescent element shown in FIG. 3.

FIG. 5 is a diagram for illustrating a thin film state of an Al electrode, which is a cathode of the organic electroluminescent device of FIG. 4A, as an example; FIG.

6 is a cross-sectional view showing an EL device as a second embodiment according to the present invention;

7A to 7D are manufacturing process diagrams of the electroluminescent element shown in FIG. 6.

* Description of the main parts of the drawings *

100 organic EL device 101 glass substrate

102 semiconductor layers 102a and 102b source / drain regions

102c: channel region 103: gate insulating film

104: gate electrode 105: interlayer insulating film

106: electrode line 107: planarization insulating film

108, 308: pixel electrode 109: insulating film

110: electron injection layer 111: electron transport layer

112: organic light emitting layer 113: hole transport layer

114: hole injection layer 115: common electrode

116: protective film 118: light emitting unit

300, 600: EL device 608: electrode for surface roughness

A: Thin Film Transistor

The present invention relates to an electroluminescent device.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such flat panel displays include liquid crystal displays (hereinafter referred to as "LCDs"), field emission displays (FEDs) plasma display panels (hereinafter referred to as "PDPs") and electrophoresis. There is a luminescence (EL) display device. In order to improve the display quality of such a flat panel display device and to attempt to make a large screen, researches are being actively conducted.

Among flat panel displays, PDP is attracting attention as the most advantageous display device for light and simple and large screen because of its simple structure and manufacturing process. However, PDP has low luminous efficiency, low luminance and high power consumption. On the other hand, active matrix LCDs with thin film transistors ("TFTs") as switching elements are difficult to screen due to the use of semiconductor processes, but demand is increasing as they are mainly used as display elements in notebook computers. have. However, LCDs are difficult to make large areas and consume large power consumption due to the backlight unit. In addition, the LCD has a large optical loss and a narrow viewing angle due to optical elements such as a polarizing filter, a prism sheet, and a diffusion plate.

In contrast, EL display devices are classified into inorganic EL devices and organic EL devices according to the material of the light emitting layer, and are self-luminous devices that emit light by themselves and have a high response speed and high luminous efficiency, luminance, and viewing angle. There is this. Such an organic light emitting diode (OLED), which is an EL element using organic materials among the EL display elements, has a low DC driving voltage, thin film thickness, uniformity of emitted light, easy pattern formation, and light emission comparable to other light emitting devices. It has the advantages of efficiency, all color light emission in the visible region, and is a technical field that is very actively researched for application to display elements.

Herein, the organic EL device may include a bottom emission method and a top emission method according to a direction in which light is emitted. In addition, the organic EL device is classified into a passive matrix organic emitting diode (PMOELD) and an active matrix organic emitting diode (AMOELD) according to a driving method.

1 is a cross-sectional view of a conventional organic electroluminescent device.

As shown in FIG. 1, the organic electroluminescent device 100, which is one example of the related art, is defined by an area where a plurality of pixel electrodes 108 and a common electrode 105 formed on the glass substrate 101 cross each other. An organic light emitting layer 102 formed on a plurality of pixels, a thin film transistor A formed on the glass substrate 101, and a drain electrode thereof electrically connected to the pixel electrode 108, and a pixel electrode 108. The electron injection layer 110 and the electron transport layer 111 formed between the organic light emitting layer 112 and the hole transport layer 113 and the hole injection layer formed between the organic light emitting layer 112 and the common electrode 115. 114).

The thin film transistor A is formed on one region of the glass substrate 101 and includes a semiconductor layer 102 and a semiconductor layer 102 composed of source / drain regions 102a and 102b and a channel region 102c. ) And a gate insulating film 103 formed on the entire surface of the glass substrate 101 including the?) And a gate electrode 104 formed on the gate insulating film 103 above the channel region 102c.

In this case, the boundary between the source / drain regions 102a and 102b and the channel region 102c is aligned with both edges of the gate electrode 104.

In addition, an interlayer insulating film 105 is formed on the thin film transistor A to open the source region 102a and the drain region 102b. The source / drain regions 102a and 102b are formed through the open portion of the interlayer insulating layer 105. ), An electrode line 106 is electrically connected.

Further, a planarization insulating film 107 is formed on the front surface including the interlayer insulating film 105 and the electrode line 106 to open the electrode line 106 electrically connected to the drain region 102b.

In addition, a pixel electrode 108 is formed on the planarization insulating layer 107. The pixel electrode 108 is formed by depositing and patterning a metal material such as Al, and then thin film transistor A through an open portion of the planarization insulating layer 107. Is electrically connected to the drain region 102b.

In addition, an insulating film 109 made of nitride or oxide is formed between the neighboring pixel electrodes 108 so that a portion of the pixel electrode 108 is covered.

In addition, the electron injection layer 110, the electron transport layer 111, the organic light emitting layer 112, the hole transport layer 113, and the hole injection layer 1 among R, G, and B may be sequentially disposed on the pixel electrode 108. 114) is formed.

In addition, the common electrode 115 is deposited on the hole injection layer 114 by depositing a material such as ITO and IZO, which are translucent or transparent conductive materials, and the protective layer 116 is formed on the common electrode 115.

However, in the conventional organic EL device 100 manufactured as described above, the pixel electrode 108 which is the cathode electrode is made of pure metal, such as Al, and has a thickness of 20 nm to 50 nm, and the upper portion of the planarization insulating film 107 and the insulating film. 109 and the lower portion of the electron injection layer 110, as shown in FIG. 2, the Al electrode, which is a pixel electrode (8 of FIG. 1), has a poor surface roughness, resulting in deterioration of light emission characteristics. Will occur.

Accordingly, there is a problem that the production yield as a display element is lowered.

In order to solve the above problems, the present invention provides a method of increasing the surface roughness of the surface of the thin film of the cathode by increasing the luminous efficiency of the cathode by forming a doped material of either Si or Ni. There is a purpose.

Another object of the present invention is to provide an improved production yield as a display element at the time of manufacturing such an electroluminescent element.

In order to achieve the above object, the present invention is formed on a substrate and a substrate including a non-light emitting region including a thin film transistor and a patterned light emitting region other than the non-light emitting region, and is electrically connected to the drain of the thin film transistor, The first electrode includes a first electrode formed by doping a predetermined amount of one of Ni or two materials, a light emitting part formed on the first electrode, and a second electrode formed on the light emitting part.

According to another feature of the invention, the first electrode is characterized in that it is formed by containing a predetermined amount of 0.1% to 10% of any one material of Si or Ni or both materials.

According to another feature of the invention, the first electrode and the second electrode is characterized in that the cathode electrode and the anode electrode.

According to another feature of the invention, the light emitting portion comprises an organic light emitting layer.

According to still another aspect of the present invention, a non-light emitting region including a thin film transistor and a substrate including a patterned light emitting region other than the non-emitting region are formed on the substrate and are electrically connected to a drain of the thin film transistor. A surface roughness electrode formed by doping any one of Si or Ni or a predetermined amount of the two materials on either the upper part or the lower part of the first electrode and the first electrode, and a light emitting part and a light emitting part formed on the surface roughness electrode It includes a second electrode formed on.

According to another feature of the invention, the first electrode comprises any one or alloy of Al, Ag, Fe, Au, Cu, Mg, Cr, Mo, LiF, ITO, IZO.

According to another feature of the invention, the thickness of the surface roughness electrode is characterized in that 1nm to 15nm.

According to another feature of the invention, the first electrode and the second electrode is characterized in that the cathode electrode and the anode electrode.

According to another feature of the invention, the light emitting portion comprises an organic light emitting layer.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention in more detail.

<First Embodiment>

3 is a cross-sectional view showing an EL device as a first embodiment according to the present invention. First, the EL device according to the present invention is provided in the same manner as the EL device described above with reference to FIG. 1. However, in the electroluminescent device according to the present invention, the cathode electrode, which is a pixel electrode electrically connected to the drain of the thin film transistor, is formed by doping any one material of Si or Ni or a predetermined amount of the two materials. Such an electroluminescent device according to the present invention will be described in detail with reference to FIG. 3.

As shown in FIG. 3, the electroluminescent device 300 according to the present invention includes a plurality of pixel electrodes formed on the glass substrate 101 in the same manner as the organic electroluminescent device 100 described above with reference to FIG. 1. 308 and the organic light emitting layer 112 formed on a plurality of pixels defined by regions where the common electrode 115 intersects, and a drain electrode formed on the glass substrate 101, and the drain electrode is electrically connected to the pixel electrode 308. The thin film transistor A connected to each other, the electron injection layer 110 and the electron transport layer 111 formed between the pixel electrode 108 and the organic light emitting layer 112, and the organic light emitting layer 112 and the common electrode 115. It is composed of a hole transport layer 113, a hole injection layer 114 formed between the laminated.

The semiconductor layer 102 including the source / drain regions 102a and 102b and the channel region 102c, the gate insulating film 103, the gate electrode 104, the interlayer insulating film 105, and the electrode line 106 ), The planarization insulating film 107, the insulating film 109, the protective film 116, and the like.

Such components of the electroluminescent device 300 according to the present invention and the organic relationship therebetween are the respective components provided in the electroluminescent device 100 described above with reference to FIG. Since the organic relationship between the two is the same, each description thereof will be omitted below.

However, in the electroluminescent device according to the present invention, the pixel electrode 308, which is a cathode electrode electrically connected to the drain of the thin film transistor, is formed by doping any one material of Si or Ni or a predetermined amount of the two materials. Looking at the manufacturing process of the electroluminescent device according to the present invention in detail as shown in Figure 4a to 4d.

4A to 4D are manufacturing process diagrams of the electroluminescent element shown in FIG. 3.

As shown in FIG. 4A, first, a semiconductor layer 102 is formed on a glass substrate 101 by using polysilicon, for example, for use as an active layer of a thin film transistor, and then a region in which the thin film transistor is to be formed. That is, the semiconductor layer 102 is patterned so as to remain only in the thin film transistor predetermined region.

Thereafter, the gate insulating film 103 and the gate electrode conductive film are sequentially stacked on the entire surface, and then the gate electrode 104 is formed by patterning the conductive film for the gate electrode so as to remain on one region of the patterned semiconductor layer 102.

Thereafter, an impurity such as boron (B) or phosphorus (P) is injected into the semiconductor layer 102 using the gate electrode 104 as a mask, followed by heat treatment to form source / drain regions 102a and 102b of the thin film transistor. do. In this case, impurity ions are not implanted into the channel region 102c of the semiconductor layer 102.

Thereafter, an interlayer insulating film 105 is formed on the entire surface, and the interlayer insulating film 105 and the gate insulating film 103 are selectively removed to expose the source / drain regions 102a and 102b of the thin film transistor to form a contact hole. do.

Thereafter, the first metal film is formed to a thickness sufficient to fill the contact hole, and the first metal film is selectively removed so as to remain only in the contact hole and the region adjacent thereto, so as to be electrically connected to the source / drain regions 102a and 102b, respectively. To form an electrode line 106 connected to.

Thereafter, the planarization insulating layer 107 is formed on the entire surface to planarize the entire surface, and the planarization insulating layer 107 is selectively removed so as to expose the electrode line 106 connected to the drain region 102b to form a contact hole. A second metal film having high reflectance and work function values such as Al, Mo, AgAu, and the like was deposited on the entire surface. At this time, the second metal film is also formed in the contact hole so that the second metal film is connected to the electrode line 106 under the contact hole.

Thereafter, the second metal film is selectively removed to form the pixel electrode 308, which is a cathode electrode electrically connected to the lower drain region 102b through the electrode line 106. At this time, the pixel electrode 308 of the electroluminescent device according to the present invention is formed by doping a material of any one of Si or Ni or a predetermined amount of 0.1% to 10% of the Al material electrode. Since Si or Ni has a high coefficient of thermal expansion due to the properties of the material, the pixel electrode 308 subjected to the firing process at the time of electrode formation may be the planarization insulating layer 107 and the insulating layer 109 and the electron injection layer 110 to be formed later. Surface roughness of the liver is increased to improve luminous efficiency.

Thereafter, as shown in FIG. 4B, an insulating film 109 is formed to cover a portion of the pixel electrode 308 between the neighboring pixel electrodes 308.

Thereafter, as shown in FIG. 4C, the electron injection layer 110 and the electron transport layer 111, which are the light emitting units 118, are deposited and the R, G, and B light emitting layers 112 are formed by using a shadow mask. Are deposited respectively. In addition, the hole transport layer 113 and the hole injection layer 114 and the like are deposited on the entire surface. Here, the light emitting unit 118 according to the present invention includes an organic R, G, B light emitting layer 112 to emit light by depositing an organic material, the present invention is not limited to this inorganic R, G to emit light by depositing an inorganic material And a B light emitting layer.

Thereafter, as shown in FIG. 4D, the common electrode 115, which is an anode electrode such as ITO and IZO, which is a transparent conductive material, is formed on the light emitting unit 118, and the light emitting unit 118 is protected from oxygen or moisture. In order to form the protective film 116 and then attach the protective cap using a sealant and a transparent substrate, although not shown, an organic EL device is completed.

The organic electroluminescent device (300 of FIG. 3) according to the present invention is formed by the pixel electrode 308 serving as the cathode electrode being doped with a metal material such as Al, a material of Si or Ni, or a predetermined amount of these two materials. Therefore, since Si or Ni has a high coefficient of thermal expansion due to the properties of the material, the planarization insulating film 107, the insulating film 109, and the electrons are formed even when the pixel electrode 308 subjected to the firing process at the time of electrode formation has a thickness of 20 nm to 50 nm. Surface roughness between the injection layers 110 is increased to increase the luminous efficiency. Accordingly, the production yield as the display element is improved. This can be seen that the surface roughness is improved by comparing with reference to FIGS. 2 and 5.

Meanwhile, a surface roughness electrode formed by doping any one of Si or Ni or a predetermined amount of two materials is further formed on either part of the cathode electrode or the cathode of the electroluminescent device according to the present invention to further improve surface roughness. It can be raised to further improve the luminous efficiency, look at in detail with respect to the electroluminescent device according to the present invention as shown in FIG.

Second Embodiment

6 is a cross-sectional view showing an EL device as a second embodiment according to the present invention. First, the EL device according to the present invention is provided in the same manner as the EL device described above with reference to FIGS. 1 and 3. However, the electroluminescent device according to the present invention includes a surface roughness electrode formed by doping any one of Si or Ni or a predetermined amount of these two materials on top of a cathode electrode, which is a pixel electrode electrically connected to a drain of a thin film transistor. It is further provided. Looking at the electroluminescent device according to the present invention in detail, as shown in FIG.

As shown in FIG. 6, a plurality of electroluminescent devices 600 according to the present invention may be provided on the glass substrate 101 in the same manner as the electroluminescent devices 100 and 300 described above with reference to FIGS. 1 and 3. The organic light emitting layer 112 is formed on a plurality of pixels defined by regions where the formed pixel electrode 108 and the common electrode 115 intersect, and the drain electrode is formed on the glass substrate 101. ), The electron injection layer 110, the electron transport layer 111, and the organic light emitting layer 112 that are stacked between the pixel electrode 108 and the organic light emitting layer 112. The hole transport layer 113 and the hole injection layer 114 formed between the electrodes 115 are laminated.

The semiconductor layer 102 including the source / drain regions 102a and 102b and the channel region 102c, the gate insulating film 103, the gate electrode 104, the interlayer insulating film 105, and the electrode line 106 ), The planarization insulating film 107, the insulating film 109, the protective film 116, and the like.

Such components of the electroluminescent device 600 according to the present invention and the organic relationship therebetween are shown in FIG. 1 and FIG. 3, respectively. Since the components and the organic relationship between them are the same, each description thereof will be omitted below.

However, in the electroluminescent device according to the present invention, a material of any one of Si or Ni, or a predetermined amount of the two materials is formed on any one of the upper and lower portions of the pixel electrode 108 which is a cathode electrode electrically connected to the drain of the thin film transistor. A doping surface roughness electrode 608 is further provided. Looking at the manufacturing process of the electroluminescent device according to the present invention in detail as shown in Figure 7a to 7d.

7A to 7D are manufacturing process diagrams of the electroluminescent element shown in FIG. 6.

As shown in FIG. 7A, a semiconductor layer 102 is formed on a glass substrate 101 by using polysilicon, for example, for use as an active layer of a thin film transistor, and then a region where a thin film transistor is to be formed. That is, the semiconductor layer 102 is patterned so as to remain only in the thin film transistor predetermined region.

Thereafter, the gate insulating film 103 and the gate electrode conductive film are sequentially stacked on the entire surface, and then the gate electrode 104 is formed by patterning the conductive film for the gate electrode so as to remain on one region of the patterned semiconductor layer 102.

Thereafter, an impurity such as boron (B) or phosphorus (P) is injected into the semiconductor layer 102 using the gate electrode 104 as a mask, followed by heat treatment to form source / drain regions 102a and 102b of the thin film transistor. do. In this case, impurity ions are not implanted into the channel region 102c of the semiconductor layer 102.

Thereafter, the interlayer insulating film 105 is formed on the entire surface, and the interlayer insulating film 105 and the gate insulating film 103 are selectively removed so that the source / drain regions 102a and 102b of the thin film transistor are exposed. Form.

Thereafter, the first metal film is formed to a thickness sufficient to fill the contact hole, and the first metal film is selectively removed so as to remain only in the contact hole and the region adjacent thereto, so as to be electrically connected to the source / drain regions 102a and 102b, respectively. To form an electrode line 106 connected to.

Thereafter, the planarization insulating layer 107 is formed on the entire surface to planarize the entire surface, and the planarization insulating layer 107 is selectively removed so as to expose the electrode line 106 connected to the drain region 102b to form a contact hole. A second metal film having high reflectance and work function values such as Al, Mo, AgAu, and the like was deposited on the entire surface. At this time, the second metal film is also formed in the contact hole so that the second metal film is connected to the electrode line 106 under the contact hole.

Thereafter, the second metal film is selectively removed to form a pixel electrode 108 which is a cathode electrode electrically connected to the lower drain region 102b through the electrode line 106, and formed on the pixel electrode 108. A surface roughness electrode 608 formed by doping a material of either Si or Ni or a predetermined amount of the two materials is further formed. Here, the pixel electrode 108 is a thickness of 20nm to 150nm electrode having a material containing any one or any alloy of Ag, Fe, Au, Cu, Mg, Cr, Mo, LiF, ITO, IZO Electroconductivity is imparted to form the surface, and the surface roughness electrode 608 is formed to a thickness of 1 nm to 15 nm to improve surface roughness.

When the thickness of the surface roughness electrode 608 formed by doping any one of Si or Ni or a predetermined amount of these materials is 20 nm or less, the crystal state between the materials of the surface roughness electrode 608 is optimized. While the thermal expansion coefficient is increased due to the properties of the material, the surface roughness electrode 608 and the pixel electrode 108 which have undergone the firing process at the time of forming the electrode are planarized insulating film 107 and the insulating film 109 to be formed later, and As the surface roughness between the electron injection layers 110 is increased, the luminous efficiency is improved.

Thereafter, the manufacturing process of the electroluminescent device according to the present invention described above with reference to FIGS. 7B to 7D is formed through the same sequential process as the manufacturing process of the electroluminescent device described above with reference to FIGS. 4B to 4D. Each of these descriptions will be omitted below.

Such an organic electroluminescent device (600 of FIG. 6) according to the present invention has a material of any one of Si, Ni, or both of these materials on top of the pixel electrode 108 including materials providing conductivity that is a cathode electrode. Since the surface roughness electrode 608 formed by doping a predetermined amount is further provided, the planarization insulating film 107, the insulating film 109, and the electron injection layer are performed while the electroluminescence is performed faster than the organic electroluminescent device described above with reference to FIG. 3. The surface roughness between the surfaces 110 becomes higher, so that the luminous efficiency is further increased. Accordingly, the production yield as a display element is further improved.

Meanwhile, for convenience of description, the surface roughness electrode 608 according to the present invention is illustrated as being formed on the upper portion of the pixel electrode 108. However, the present invention is not limited thereto, and the surface roughness electrode 608 is the pixel electrode. It is also possible to further increase the surface roughness between the planarization insulating film 107, the insulating film 109, and the electron injection layer 110 by forming the lower portion of the 108 or the upper and lower portions of the pixel electrode 108.

In addition, for convenience of description, the pixel electrode 308, which is a cathode electrode, is formed on the planarization insulating layer 107 and the electron injection layer 110 and the electron transfer are sequentially formed on the pixel electrode 308. The layer 111, the organic R, G, and B light emitting layers 112, the hole transport layer 113, and the hole injection layer 114 are illustrated as being described above, but the present invention is not limited thereto. 115 is formed on the planarization insulating layer 107, and the hole injection layer 114, the hole transport layer 113, the organic R, G, and B emission layers 112 and the electron transport layer are sequentially formed on the common electrode 115. 111 and the electron injection layer 110 may be formed. This is to increase the luminous efficiency without affecting the aperture ratio as much as possible by changing the driving method or the two electrode materials when the organic electroluminescent element is electroluminescent in one or both directions.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

According to the electroluminescent device of the present invention made as described above, the following effects can be obtained.

First, the cathode is formed by doping a material of either Si or Ni or a predetermined amount of the two materials, thereby increasing the surface roughness of the surface of the thin film of the cathode and increasing the luminous efficiency.

Second, there is another effect that can improve the production yield as a display device when manufacturing the electroluminescent device.

Claims (9)

A substrate including a non-emitting region including a thin film transistor and a patterned emitting region other than the non-emitting region; A first electrode formed on the substrate and electrically connected to the drain of the thin film transistor and formed by doping any one of Si or Ni or a predetermined amount of the two materials; A light emitting part formed on the first electrode; An electroluminescent device comprising a second electrode formed on the light emitting portion. The method of claim 1, The first electrode is an electroluminescent device, characterized in that the material is doped with any one of the Si or Ni or 0.1% to 10% of the two materials. The method of claim 1, And the first electrode and the second electrode are a cathode electrode and an anode electrode. The method of claim 1, The light emitting part includes an organic light emitting layer. A substrate including a non-emitting region including a thin film transistor and a patterned emitting region other than the non-emitting region; A first electrode formed on the substrate and electrically connected to a drain of the thin film transistor; A surface roughness electrode formed by doping any one of Si or Ni or a predetermined amount of the two materials on any one of the upper and lower portions of the first electrode; A light emitting part formed on the surface roughness electrode; An electroluminescent device comprising a second electrode formed on the light emitting portion. The method of claim 5, The first electrode includes any one of Al, Ag, Fe, Au, Cu, Mg, Cr, Mo, LiF, ITO, IZO or an alloy thereof. The method of claim 5, The surface roughness electrode has a thickness of 1 nm to 15 nm. The method of claim 5, And the first electrode and the second electrode are a cathode electrode and an anode electrode. The method of claim 5, The light emitting part includes an organic light emitting layer.

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